214 research outputs found

    Applying Grounded Theory to Conceptual Data Modeling: Effects of Constant Comparative Method

    Get PDF
    This article presents an experimental design and the pilot experiment results of applying grounded theory to conceptual datamodeling. The objective of this study is to develop a procedural method for concept discovery, which is essential in datamodeling. The research focuses on addressing the lack of procedural methods for understanding domain knowledge by datamodeler. The key idea of this article is that conceptual modeling can be strengthened by applying a constant comparativemethod of coding and analysis, which has been used to discover concepts in the social sciences. This article contributes newknowledge about the effects of applying interdisciplinary concept discovery in the context of conceptual data modeling. Theresults of the pilot experiment show that the proposed approach would have positive results

    Examination of the Dimensions of Biological Age

    Get PDF
    The concept of biological age has been used more and more frequently in aging research in attempts to measure the progress of the biological aging process as opposed to the simple passage of time. Several approaches to quantify biological age have been utilized, including the use of biomarkers in the form of serum analytes, epigenetic markers, and deficit or frailty indices. Among these methods, the deficit index possesses a theoretical basis grounded in systems biology by incorporating networks, with their emergent properties, to describe the complex aging system. Application of the deficit index in human aging studies points to the increased energetic demands posed by an aging system that is losing integration. Different aspects of mitochondrial function appear to be responsible in males and females. The gut microbiome loses complexity in tandem with the host, as biological age increases, with likely impact on host metabolism and immunity. Specific DNA methylation changes are associated with biological age. They suggest declining connectivity within the aging network, at the cellular level. The deficit/frailty index may account for at least part of the departure at older ages of the observed mortality in the population from the exponential increase modeled by the Gompertz equation

    Iron deficiency increases blood concentrations of neurotoxic metals in children

    Get PDF
    Iron deficiency affects approximately one-third of the world's population, occurring most frequently in children aged 6 months to 3 years. Mechanisms of iron absorption are similar to those of other divalent metals, particularly manganese, lead, and cadmium, and a diet deficient in iron can lead to excess absorption of manganese, lead, and cadmium. Iron deficiency may lead to cognitive impairments resulting from the deficiency itself or from increased metal concentrations caused by the deficiency. Iron deficiency combined with increased manganese or lead concentrations may further affect neurodevelopment. We recently showed that blood manganese and lead concentrations are elevated among iron-deficient infants. Increased blood manganese and lead levels are likely associated with prolonged breast-feeding, which is also a risk factor for iron deficiency. Thus, babies who are breast-fed for prolonged periods should be given plain, iron-fortified cereals or other good sources of dietary iron

    A Facile Fabrication and Transfer Method of Vertically Aligned Carbon Nanotubes on a Mo/Ni Bilayer for Wearable Energy Devices

    Get PDF
    Carbon nanotubes are a promising material for flexible/wearable electrochemical device due to their mechanical softness, chemical stability, and high conductivity. Furthermore, the vertically aligned form of carbon nanotubes (VACNTs) have a large surface area due to their unique three-dimensional (3D) nanostructure. Thus, VACNTs are particularly useful for wearable electrochemical sensors and/or energy devices. However, VACNTs are generally grown via a high-temperature chemical vapor deposition process, which requires a rigid substrate. As a flexible/wearable device platform, therefore, VACNTs should be transferred from rigid substrates to soft substrates. Here, a facile fabrication and transfer method of a unique 3D nanostructure, that is, VACNTs on the Mo/Ni bilayer, for high performance flexible/wearable devices is reported. After growth of VACNTs on a Mo/Ni bilayer, VACNTs with the Mo/Ni bilayer can be easily peeled-off from the SiO2 wafer by using weak adhesion of Ni to SiO2 for transfer printing onto polymeric/elastomeric substrates. Moreover, the Mo layer helps facile growth of VACNTs, and the Mo/Ni bilayer underneath VACNTs maximizes the lateral current flow. The proposed 3D nanostructure (VACNTs on the Mo/Ni bilayer) is successfully applied as flexible electrodes for high-performance wearable asymmetric supercapacitors.

    Wearable Fall Detector using Integrated Sensors and Energy Devices

    Get PDF
    Wearable devices have attracted great attentions as next-generation electronic devices. For the comfortable, portable, and easy-to-use system platform in wearable electronics, a key requirement is to replace conventional bulky and rigid energy devices into thin and deformable ones accompanying the capability of long-term energy supply. Here, we demonstrate a wearable fall detection system composed of a wristband-type deformable triboelectric generator and lithium ion battery in conjunction with integrated sensors, controllers, and wireless units. A stretchable conductive nylon is used as electrodes of the triboelectric generator and the interconnection between battery cells. Ethoxylated polyethylenimine, coated on the surface of the conductive nylon electrode, tunes the work function of a triboelectric generator and maximizes its performance. The electrical energy harvested from the triboelectric generator through human body motions continuously recharges the stretchable battery and prolongs hours of its use. The integrated energy supply system runs the 3-axis accelerometer and related electronics that record human body motions and send the data wirelessly. Upon the unexpected fall occurring, a custom-made software discriminates the fall signal and an emergency alert is immediately sent to an external mobile device. This wearable fall detection system would provide new opportunities in the mobile electronics and wearable healthcare.

    WEDGING OF FRICTIONAL ELASTIC SYSTEMS

    Get PDF
    We consider discrete two-dimensional elastic systems with Coulomb friction contacts, and investigate the conditions that must be satisfied if these are to be capable of becoming ‘wedged’ --- i.e. of remaining with non-zero elastic deformations when all external loads have been removed. The condition for wedging is reduced to the requirement that a prescribed set of constraint vectors should fail to positively span the N-dimensional vector space of nodal displacements. We also show that the range of admissible wedged states increases monotonically with the coefficient of friction f and that there exists a unique critical coefficient fw such that wedging is impossible for f fw

    Selective Inhibition of Bakuchicin Isolated from Psoralea corylifolia on CYP1A in Human Liver Microsomes

    Get PDF
    Bakuchicin is a furanocoumarin isolated from Psoralea corylifolia and shows several biological activities. Although there have been studies on the biological effects of bakuchicin, its modulation potency of CYP activities has not been previously investigated. Here, we investigated the inhibitory effects of bakuchicin on the activities of CYP isoforms by using a cocktail of probe substrates in pooled human liver microsomes (HLMs) and human recombinant cDNA-expressed CYP. Bakuchicin strongly inhibited CYP1A-mediated phenacetin O-deethylation with an IC 50 value of 0.43 M in HLMs. It was confirmed by human recombinant cDNA-expressed CYP1A1 and CYP1A2 with a value of 0.11 M and 0.32 M, respectively. A Lineweaver-Burk plot indicated that the inhibition mechanism of bakuchicin was competitive inhibition. Overall, this is the first study to investigate the potential CYP1A1 and CYP1A2 inhibition associated with bakuchicin and to report its competitive inhibitory effects on HLMs

    Global Lysine Acetylome Analysis of LPS-Stimulated HepG2 Cells Identified Hyperacetylation of PKM2 as a Metabolic Regulator in Sepsis

    Get PDF
    Sepsis-induced liver dysfunction (SILD) is a common event and is strongly associated with mortality. Establishing a causative link between protein post-translational modification and diseases is challenging. We studied the relationship among lysine acetylation (Kac), sirtuin (SIRTs), and the factors involved in SILD, which was induced in LPS-stimulated HepG2 cells. Protein hy-peracetylation was observed according to SIRTs reduction after LPS treatment for 24 h. We identified 1449 Kac sites based on comparative acetylome analysis and quantified 1086 Kac sites on 410 proteins for acetylation. Interestingly, the upregulated Kac proteins are enriched in glycolysis/glu-coneogenesis pathways in the Kyoto Encyclopedia of Genes and Genomes (KEGG) category. Among the proteins in the glycolysis pathway, hyperacetylation, a key regulator of lactate level in sepsis, was observed at three pyruvate kinase M2 (PKM2) sites. Hyperacetylation of PKM2 induced an increase in its activity, consequently increasing the lactate concentration. In conclusion, this study is the first to conduct global profiling of Kac, suggesting that the Kac mechanism of PKM2 in glycolysis is associated with sepsis. Moreover, it helps to further understand the systematic information regarding hyperacetylation during the sepsis process. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.1

    Locally Activating TrkB Receptor Generates Actin Waves and Specifies Axonal Fate

    Get PDF
    Actin waves are filamentous actin (F-actin)-rich structures that initiate in the somato-neuritic area and move toward neurite ends. The upstream cues that initiate actin waves are poorly understood. Here, using an optogenetic approach (Opto-cytTrkB), we found that local activation of the TrkB receptor around the neurite end initiates actin waves and triggers neurite elongation. During actin wave generation, locally activated TrkB signaling in the distal neurite was functionally connected with preferentially localized Rac1 and its signaling pathways in the proximal region. Moreover, TrkB activity changed the location of ankyrinG––the master organizer of the axonal initial segment-and initiated the stimulated neurite to acquire axonal characteristics. Taken together, these findings suggest that local Opto-cytTrkB activation switches the fate from minor to major axonal neurite during neuronal polarization by generating actin waves.C. 2019 Elsevier Ltd.11Nsciescopu
    corecore